FWIW, most of my pages on gwern.net seem like they’d count as ‘long texts’, but my just concluded font A/B test using 2 sans-serif and 2 serif fonts doesn’t see any difference in reading time when you split by serif: http://www.gwern.net/a-b-testing#fonts
I think I’ve noticed that I’m more willing to read long texts written in small font sizes than in large ones, and in sans-serif than in serif font.
I might try again to read A Gentle Introduction to Unqualified Reservations, but in a small, sans-serif typeface this time, to test this.
FWIW, most of my pages on gwern.net seem like they’d count as ‘long texts’, but my just concluded font A/B test using 2 sans-serif and 2 serif fonts doesn’t see any difference in reading time when you split by serif: http://www.gwern.net/a-b-testing#fonts
That only tests for the averages AFAICT—there might well be people who read serif fonts faster and people who read sans-serif fonts faster.
Since I don’t know whether I like the Big Endians or Little Endians, I only care about the average.